1. Field of the Invention
The present invention relates to a bag for packaging fruits or vegetables. The bag of the invention is made of opaque plastic sheet material but comprises on its rear wall a transversal perforated window made of transparent plastic sheet material. The present invention also extends to a method and apparatus for fabricating the plastic bag.
2. Brief Description of the Prior Art
Paper bags with perforated windows, such as that illustrated in FIG. 5 of U.S. Pat. No. 2,745,593 granted to C. V. Brady on May 15, 1956, are currently used for packaging potatoes. They present the drawback of absorbing too much humidity over a long period of storage, and accordingly of causing shrinking of the skin of the potatoes. High costs are also involved in their fabrication.
Examples of transparent and perforated plastic bags for packaging fruits or vegetables are disclosed in U.S. Pat. No. 2,689,678 (Wendt) issued on Sep. 21, 1954, U.S. Pat. No. 3,245,606 (Crane) granted on Apr. 12, 1966, and in the patent document NL 197809.
A first drawback of the transparent plastic bags is that they expose the fruits or vegetables to light. In the case of potatoes, such exposure to light causes appearance of health hazardous green regions.
The end slits of the bag of U.S. Pat. No. 2,689,678 will underventilate the fruits or vegetables. Concerning the plastic bag of U.S. Pat. No. 3,245,606, the high concentration of slits in a delimited zone will overventilate the fruits or vegetables and will greatly reduce the mechanical resistance of the bag in this zone.
Patent document NL 197809 discloses a bag comprising perforations distributed over its entire surface. When bags as disclosed in this document are filled with fruits or vegetables and are stacked upon storage, up to 40% of the perforations are closed by the fruits or vegetables, and/or by the surrounding plastic bags. Proper ventilation of the fruits or vegetables is thereby prevented.